This invention relates to strand heating furnaces, or more particularly to improvements in the strand heating mechanism of a panel type furnace, such as illustrated and described in U.S. Pat. No. 2,869,846 to Bloom.
Panel type furnaces have achieved a high degree of acceptance in the steel industry due to their general convenience and reliability. Such furnaces have been used to heat steel strip moving in a fixed path continuously at speeds up to several hundred feet per minute. The furnaces typically comprise one or more pairs of oppositely disposed panels provided with radiant gas burners. As exemplary prior art panel measures about 4 feet by 5 feet and contains 30 burners arranged in five rows with six burners each.
While such furnaces and the related line equipment were designed for continuous operation, it is necessary, often frequently, to shut down the operation for threading broken strips, maintenance, repairs and other malfunctions. To facilitate such work in and around the furnace, means were provided for moving the furnace sideways to a position away from the fixed path of the strip. The construction and description of one such means is set forth in the Bloom patent noted earlier. Additionally, the art of panel type furnaces has progressed further with the addition of improved air seals, improvements in refractory materials, improved designs for the interchangeability or replacement of panels, and to various means for controlling heat loss from the furnace.
The present invention relates to a further improvement in the art of panel type furnaces and is compatible with and used in conjunction with each or all of the improvements noted above. This invention relates to one area which has received little attention as a potential area for improvement, for, practitioners in the art believed an array of burners was needed to insure sufficient heating of the rapidly moving steel strip. Perhaps the apparent absence of concern for conserving energy or fuel may have misled such practitioners to the conclusion that multiple burners were the only answer, and that an array of burners was the most efficient and practical method of heating the steel strip.
Through improved maintenance control and fuel consumption, it was discovered that each exemplary feature below could be achieved, along with improved product quality and quantity of material processed, by the newly designed and operated furnace panel of this invention. For example, by the addition of the furnace panel of this invention to the strip heating mechanism of a hot dip coating line, product quality was improved, the quantity of coated steel produced was increased, the fuel consumption per ton of steel heated was lowered, and the level and extent to maintenance required to operate the heating mechanism was lowered. Such improvements will become apparent from a reading of the description to follow.